Fertilizing indoor plants: when how and with what fertilizer?

In terms of fertilizing houseplants, it’s no exaggeration to say that this is a a la carte menu because all these plants do not have the same needs. In any case, abuse is absolutely avoided in order to avoid overdoses which are very detrimental to the plants. It is essential to take into account different factors, such as the type of plant but also the growing medium and possible nutrient deficiencies, the season and the fertilizers themselves. Let’s do a check in.

When should you fertilize your indoor plants?

Indoor plants are grown in pots or trays, and even if the container is large, the volume of substrate is still limited compared to growing in the garden, in the ground, so that it devitalizes quite quickly. . In order for it to continue to nourish the plant, it is absolutely essential to replenish the growing medium with nutrients such as minerals and trace elements. It is for this purpose that we regularly add fertilizer. Some plants turn out to be much more greedy than others, for example just before the formation of flower buds, when they are in full bloom or still in full growth.

During the period of vegetative rest, it is of course strongly discouraged to distribute fertilizer to plants. They have very few needs since they are in dormancy. This period is more or less long depending on the plants. For example, for cacti in arid zones, it starts in September and ends in April. We also refrain from fertilizing a houseplant during the two months following its purchase because a fertilizer has already been integrated into the substrate.

The fertilization frequency varies depending on the plants but also on the fertilizer used, namely:

  • Liquid fertilizer:
    • one intake every two to four weeks for fast-growing houseplants,
    • one intake every eight weeks for slow growing plants.
  • Fertilizer in sticks: a contribution every five to eight weeks, knowing that for certain plants, one is satisfied with a fertilization every twelve weeks.
  • Granular fertilizer: a single application at the beginning of spring.

How to fertilize indoor plants?

Whatever the needs of houseplants, there is one thing that all specialists agree on: it is absolutely necessary avoid over-fertilization. To make it easier and there is less risk of overdosing one or other of the components, you can turn to a fertilizer ready to be diluted or even ready to use. But be careful, however, to always respect the instructions on the bottle, whether in terms of dosage or even frequency.

There are different fertilizers that vary in nutrient content so that each is perfectly suited to the type of houseplants being grown. Whichever one you opt for, moderation is always in order. Believing they are doing the right thing, many novice gardeners have seen their plants die from overdosing.

The proportion of nitrogen (N), phosphorus (P) and potassium (K) is always indicated in this order (NPK) on the container, each letter being followed by a number. Do not hesitate to seek advice at the time of purchase since the formulation of a fertilizer must be chosen according to the species to be fertilized.

What fertilizer to use for indoor plants?

Green plants and indoor flowering plants need very specific fertilizers. The first must benefit from a fertilizer rich in nitrogen because it promotes the growth as well as the greening of the foliage. The seconds produce more than flowers with a fertilizer rich in potash. But that’s not all: to boost the development of root system and increase the resistance of a plant, care should be taken to administer a fertilizer rich in phosphorus. Other nutrients are just as essential for the general good health of indoor plants, such as calcium, magnesium or even sulphur.

We can well imagine that it is easier for amateur gardeners to have fertilizer products already dosedsuch as liquid fertilizer, stick fertilizer and coated granular fertilizer.

Liquid fertilizer for indoor plants

This is a concentrated fertilizer that it is essential to dilute in water before fertilizing your plants. Thus, we find, among other things, liquid fertilizer for Orchids, for cacti, for citrus fruits in pots, for exotic plants, for green plants or even for bonsai, etc…. The choice is vast. With his measuring cap, it is the simplest to use since it is enough to mix it with the irrigation water. This fertilizer is distributed evenly in the substrate.

Fertilization is carried out throughout the growth period (i.e. between April and September) or before and during the flowering period. In this way, it is not very complicated to have splendid indoor plants.

Finally, it should be noted that the greatest caution is required: never distribute fertilizer if the growing medium is dry. In this case, it is absolutely necessary to first water abundantly in order to properly rehydrate the growing medium and it is only after that that the necessary dose of fertilizer can be distributed. If this precaution is not taken, fertilization on a dry substrate (even with a well-diluted fertilizer) causes burns at the root level.

Fertilizer sticks for indoor plants

Stick fertilizer, while also convenient, is harder to use than liquid fertilizer. You have to push it into the substrate until you can no longer see the upper part of the stick. Nutrients are then gradually released in the soil with each watering, for 30 to 60 days.

Sticks are appreciated by anyone who does not want to worry about having to dilute a fertilizer or who is afraid of forgetting to fertilize their houseplants. Moreover, it is a kind of gentle method of fertilization with which there is no risk of exposing your plants to an overdose. It is of course necessary to follow the instructions for use to the letter. Be careful however, the sticks do not exempt you from watering your plants as soon as necessary.

Fertilizer in coated granules for indoor plants

Cet slow release fertilizer is easy to use since it is sufficient to place the granules on the surface of the growing medium for each potted plant. A handful is more than enough. In terms of advantages, it is quite similar to stick fertilizer since the nutrients are released in small quantities during the various waterings and very gradually without having to intervene, but this time for a full season. Again, there is no risk of forgetting or exposing your plants to an overdose.

Finally, when repotting, it is quite possible to mix a handful of granular fertilizer with the new substrate unless you opt for a potting soil because it already contains the necessary nutrients. Adding a fertilizer within 8 to 10 weeks would only result in exposing the plant to an overdose.

Leave a Comment